for i := range classes {
		if i == 0 {
			continue
		}
		c := &classes[i]
		psize := c.npages * pageSize
		new_size := (psize / (psize / c.size)) &^ (largeSizeDiv - 1)
		if new_size > c.size {
			c.size = new_size
		}
	}

	if len(classes) != 68 {
		panic("number of size classes has changed")
	}

	for i := range classes {
		computeDivMagic(&classes[i])
	}